Answer: A) The triangles made by the tree and its shadow and Rachel and her shadow are similar.
Explanation:
Since both the tree and the girl is standing vertical to the ground making right angle .
If we assume that the given measure took at same time, then the angle made by sun rays would be same for tree and Rachel. [Corresponding angles]
Thus triangles made by both of them are similar.
Since, the corresponding sides of similar triangles are proportional.
Therefore, the statement BEST explains the reason that Rachel can use a proportion to estimate the length of the tree :-
A) The triangles made by the tree and its shadow and Rachel and her shadow are similar.